Computer systems and network

Which of the following is true about packets?

• Packets arrive at the receiving computer in the same order that they are sent from the sending computer.

• Packets can arrive at the receiving computer in a different order than sent by the sending computer.

• When sent by a sending computer packets are guaranteed to arrive at the receiving computer.

• One sending file will contain one packet.

Answer explanation

Packets can arrive at the receiving computer out of order. TCP protocol will arrange the packets in order based on the packet number. Since packets can follow any path and often will choose different paths in the same data stream, they will travel different distances and require different times to reach the receiving computer.

Which characteristics of internet protocols have helped fuel the rapid growth of the internet? Select TWO answers.

• Internet standards cannot be altered, so different companies can focus on development.

• Internet protocols are open (nonproprietary).

• Internet protocols are designed to be useful for a growing population of users.

• The design of internet protocols involves large profits that motivate companies to innovate internally with no outside feedback.

Answer explanation

Internet standards are free and available to any company wanting to connect their products to the internet. These open protocols ensure that hardware and software developed by different companies can communicate with each other on the internet. The changing nature of the internet requires that protocols be flexible and dynamic. The internet protocols are designed to benefit the internet community, not one particular company.

Which of the following internet protocols defines how computers send packets of data to each other?

• HTTP

• TCP

• IP

• UDP

Answer explanation

Transmission control protocol (TCP) is a protocol that defines how computers send packets of data to each other. Data traveling in the internet is broken down into small chunks of data called packets. TCP protocols guide the rules on how data are subdivided into packets before transmission.

Which of the following protocols is responsible for addressing and routing your online requests?

• HTTP

• TCP

• IP

• UDP

Answer explanation

Internet protocol (IP) is responsible for addressing and routing packets on a network.

When is it advantageous to use UDP instead of TCP?

• UDP should be used when the IP address of the receiving computer is not known.

• UDP should always be used when available since UDP is faster and more reliable than TCP.

• UDP should be used when a guarantee is required that the order of data at the sending computer matches the order of data arriving at the receiving computer.

• UDP should be used when the speed of data transfer is more important than error correction.

Answer explanation

TCP gives a guarantee that the order of data at the receiving end is the same as on the sending end, while UDP has no such guarantee. UDP is frequently used for live broadcasts and online games. UDP is faster than TCP but is less accurate.

Many types of computing devices made by many types of companies can all access the internet. Which of the following makes this access possible?

• Redundancy

• Open standards and protocols

• Fault tolerance

• Large bandwidth

Answer explanation

Open, nonproprietary communication protocols are used so that any computing device can communicate with another computing device. If the standards were not openly shared, using devices made by different companies would be more difficult.

Why are most websites designed to work within the boundaries of current web protocols, even when that limits the website’s capabilities?

• Since the protocols are supported by all current web browsers, potential incompatibilities are minimized.

• It is illegal to go beyond the boundaries of current protocols.

• Current protocols are the limit of web technology, so going further is impossible.

• If a protocol is exceeded, an ISP will assume the website to be broken or malicious and block it.

Answer explanation

Utilizing protocols that are not current means that most web browsers would be incompatible. This makes no sense for a website, which typically requires as many people as possible to be able to view it.

(B) There is no legal body that controls the boundaries of current protocols.

(C) Major companies, such as Google, are creating new protocols and web standards using current technology, which can lead to some differences between browsers.

(D) ISPs rarely filter based on the website’s behavior; ISPs block only if websites are reported or contain banned content.

What is the purpose of transitioning from IPv4 to IPv6?

• IPv4 has been found to be too insecure for modern communication.

• The rise of internet-connected devices means that the number of available unique IPv4 addresses is sharply decreasing, and IPv6 will allow for more addresses.

• IPv4 is too slow to be useful in modern communications.

• It is easier to spoof an IPv4 address, as compared to an IPv6 address.

Answer explanation

IPv4 supports 2³² (4,294,967,296) addresses. Since one address must be assigned to every device, whether client or server, the number of open addresses is slowly decreasing. IPv6 increases the length of IP addresses and, therefore, supports far more addresses overall.

(A) The IP protocol is not related to security.

(C) The IP protocol is not related to speed.

(D) Address spoofing is simply replacing one address with another, regardless of whether the original address is IPv4 or IPv6.

How does redundancy improve the scaling of the internet?

• Redundancy leads to every communication being repeated, which keeps the data from being lost.

• Redundancy leads to every communication being repeated, which ensures that the connected devices do not disconnect from each other.

• Redundancy makes connections more reliable, which means that more devices are able to communicate without interruption.

• Redundancy makes connections more reliable, which ensures that computers are always on the internet.

Answer explanation

Redundancy means that computers can stay connected even when a connection is damaged, as there are other connections that pick up the slack. This means that communications are firmer and that adding new devices is easier since the communications required to set them up can still be performed.

(A) and (B) Redundancy does not refer to repeated communications.

(D) Computers can be taken off the internet through means not including connection (such as power loss, corrupted drivers, and turning off the device).

How many lines need to be cut to isolate A completely?

• 1 lines

• 3 lines

• 4 lines

• 5 lines

Answer explanation

This is an example of a decentralized network. To isolate A completely, 3 lines must be cut. This is demonstrating redundancy. If only 1 of the lines was damaged computer, A could still communicate with no disruption.